The classification of particles according to their size and/or weight is often used in mineral processing. In order to classify these particles it is common to locate the particles in a solution to form a slurry. This slurry is then passed through various types of equipment in order to separate the particles into different sizes and/or densities.
A problem using a slurry to classify particles is that air is often formed or entrained within the slurry as the slurry moves through various types of processing equipment in a processing plant. Air bubbles formed within the slurry can cause problems with the movement of the slurry through a processing plant. For example, aeration of the slurry can reduce the efficiency of a pump used for pumping of the slurry through the processing plant. Further, aeration of the slurry can cause cavitation and premature wear of the impellor of a pump. This can lead to higher maintenance costs and premature failure of the pump.
Air bubbles formed within the slurry can also cause complications when trying to classify the particles using classifying equipment. Classifying equipment typically relies on movement of the particles within the slurry based on the size and/or weight of the particles. Air bubbles located within the slurry can effect the desired movement of the particles within the slurry. This is particularly evident in floatation processes as heavy particles can often become attached to air bubbles allowing them to pass upwardly through the classifying equipment when it is desirable for the heavy particles to remain at a bottom of the classifying equipment.